Orthogonal frequency division multiplexing or OFDM is a technique adopted in many communication systems, such as WiFi, digital audio broadcasting (DAB) and digital video broadcasting (DVB), including terrestrial (DVB-T) and handheld (DVB-H). OFDM has advantages over other techniques, advantages that include robustness against frequency selective fading and inter-symbol interference (ISI) caused by multi-path effect. OFDM techniques are particularly suited to support mobile channel communication, because OFDM techniques are able to address many problems related to mobile channels, problems that include linear distortions common in a mobile transmission, for example fading effects due to changes in antenna orientation or effects on the antenna such as placing an object (i.e., shadow) on the antenna.
A transmitted OFDM signal is sensitive to frequency errors which can introduce inter-carrier interference (ICI) leading to degraded receiver or device performance (i.e., the receiver or device misinterprets a received OFDM signal, since the original transmitted signal has been affected). In particular, an amplitude attenuation in OFDM signals causes ICI as well, resulting in misinterpreted received OFDM signals.